


An Omega After All

by DaniJayNel



Category: Shingeki no Kyojin | Attack on Titan
Genre: AU, F/F, G!P, Omegaverse, Oneshot, Smut, alpha Historia, g!p Historia, omega Ymir
Language: English
Status: Completed
Published: 2018-04-08
Updated: 2018-04-08
Packaged: 2019-04-20 10:24:07
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,550
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14258934
Author URL: https://archiveofourown.org/users/DaniJayNel/pseuds/DaniJayNel
Summary: Returning home from another exhausting day, Historia is greeted by the sweet, alluring smell of an omega in heat. But not just any omega: Ymir; who she thought was an alpha, who Historia had always assumed was out of her reach. But when Ymir is writhing and desperate for an alpha, for her, there is no way Historia can turn her away in her time of need.





	An Omega After All

**Author's Note:**

> FINALLY some good fucking omegaverse

No matter how much Historia enjoyed her classes and her student life in general (she did, though her friends thought she was odd for it), she usually came home feeling absolutely exhausted. It was the classes, the studying, having to entertain her family for lunch and sometimes even dinner, and by the time she made it home she’d barely even had a thought for herself. Historia’s favourite thing to do the second she stepped into the flat she shared with her roommate was discard her bag and jacket, stumble into her room and draw a nice bubble bath for herself. She was lucky enough to have won at rock-paper-scissors and got to stay in the room with its own bathroom.

Today, however, Historia would not make it to her usual evening bath. She wouldn’t even make it to her room. As exhausted as she was, and as distracted by that fact as she was, Historia picked up the scent almost immediately when the door to the flat clicked shut behind her. She took a cautious sniff of the air, utterly confused by what was steadily burning its way through her body. Historia’s bag slipped from her fingers and thudded to the floor, forgotten. She slowly stepped into the flat, drawn in by that warm, rich smell.

It was an omega’s heat.

At first she thought maybe Ymir had brought an omega home, but she didn’t smell an alpha anywhere, only the thick, needy, horny scent of an omega. Historia hadn’t experienced many omegas during their heat, and certainly none that smelt as good as this. She could already feel a tug between her legs, her cock straining to slide out, but she forced herself to remain in control. Maybe the omega was hurt. Maybe they needed help, and not the sexual kind.

“Ymir?” Her voice came out dark, husky. She had to cough softly to clear her throat. “Are you here?”

The scent suddenly thickened, making Historia’s entire body swell with heat. She clenched her hands into fists, heart thundering. Arousal was building like an ocean in her belly, and she could already feel her clit growing despite her best efforts to stay in control.

Ymir didn’t reply, but Historia heard a soft moan from down the hallway. She knew that going towards the scent was probably a bad idea, especially since she was quickly losing every bit of control and sense she had ever had. Historia practically stumbled down the hallway towards Ymir’s room, towards that soft moan and that tantalizing scent. The door was closed and she knew that whatever was happening was in that room. It was probably Ymir.

But how the fuck was that even possible?

Historia inhaled deeply to calm her nerves, but only succeeded in drawing in more of that smell, of that burn that made her now fully formed cock pulse in need. She groaned and leaned against the wall, panting. If she wasn’t being physically pulled forward by that smell, she would have stayed slumped against that wall forever. Instead Historia forced herself to take the final step and shove Ymir’s door open, and then she leaned against the doorframe, eyes wide, pupils fully dilated, and mouth popped open in surprise.

Ymir was curled up on her bed, brown skin flushed and covered in a layer of sweat, brown hair dishevelled and plastered to her face, and lastly her hand shoved down her panties, fingers furiously working between her legs. Historia took a massive swallow, but her mouth was absolutely dry.

Ymir moaned again.

Historia could barely fathom what she was seeing. Despite the arousal and the intense smell of an omega, she felt completely confused. Ymir wasn’t an omega. She was an alpha. Right? Her personality screamed alpha. She was tall and dark and dreamy, with a bad attitude and sharp words and eyes that could cut like a knife. People hardly ever believed that Historia was an alpha, because she was Ymir’s exact opposite. She was small and pale and blonde, and people usually assumed she was an omega before they smelt her aggression and anger and unfortunately met the underside of her fist.

Ymir had never smelt like an omega, either. Historia was certain she would have noticed. But there was no denying this, not the smell, not the desperate look in Ymir’s eyes when she glanced up at Historia, not even mad that she’d opened the door without permission.

“You’re an omega?” she blurted out stupidly. She was well aware that she was breathing too hard.

Ymir’s brows furrowed and her eyes narrowed. “That’s literally all you care about right now?”

Well, no. But she didn’t really want Ymir to know that. Yet. “I can’t believe you’re an omega.”

“I forgot to take my suppressants, okay?” Ymir buried her face into her pillow, groaning again. Heat washed down Historia’s body when she realized that Ymir hadn’t stopped her busy fingers. “It hit sooner than I thought it would, before I could hide it.”

Historia furrowed her brows. Her vision was already starting to blur, and the back of her throat burned. There was almost nothing left of her brain. Every inch of her—especially those between her legs—ached for Ymir. She wanted to rush over to the bed but she forced herself to stay rooted in place. “Hide it?” She licked her dry lips.

Ymir huffed. “Yeah, hide it. Fuck. Why are you just standing there like a fucking idiot?” She looked up again, eyes burning with lust.

Historia opened her mouth to say _something_ , but Ymir didn’t give her a chance. She crawled out of bed, straightening her long, _long_ body, and stalked forward. She had such a fierce look on her face that Historia was completely expecting a slap, but instead Ymir pulled her into the room, threw the door shut and then shoved Historia against the wall. She leaned in close, pressing their bodies together, and brushed her lips against Historia’s throat.

There she was, the alpha-like Ymir that Historia knew. It was strange, though, to know now that Ymir actually wasn’t an alpha at all, and that her every instinct should have been to submit, to beg, but she wasn’t. It should have made Historia annoyed, but instead it made her hotter. Ymir’s warm breath on her neck didn’t help.

“Do you want to leave?” Ymir asked her in a husk, panting. Heat radiated off of her, the pheromones pumping out of her in waves. Historia didn’t think she’d _ever_ been that turned on before, or that hard. “Or do you think you have what it takes to help me through this?”

 _Oh, fucking hell,_ Historia thought, stomach clenching. Her instincts were raging against her and before she could stop it, a growl worked its way out of her throat. Ymir pulled away slightly, eyes wide in surprise. When she gave a little smirk, Historia knew that she liked it.

“Are you really sure you can handle me?” Historia asked her, smirking dangerously now. Her teeth started to ache. “You may act like an alpha, Ymir, but you aren’t one. You’re an omega. Everything you are wants me to utterly use and take you.” Ymir gave her a defiant look, but she visibly shuddered, shoulders dropping. “You want me to dominate you, use your body, _fuck_ you. Don’t you?”

Ymir looked away, teeth digging into her lower lip. She furrowed her brows, seeming conflicted. Historia didn’t have the patience to give her time to come up with a smart remark. If Ymir had really wanted her to leave, she would have said so, and not nicely either. Historia felt confident that Ymir wanted her, needed her. Historia had every intention of having her.

“Sit on the edge of the bed,” Historia growled softly. Ymir looked at her, practically quivering, jaw muscles bunching, but then she quietly obeyed. A sharp thrill went through Historia as she watched. Ymir was still covered in sweat, still breathing hard. Her pupils were blown so wide that her eyes looked black. It must have taken a whole lot of control for her to sit still like that, to not collapse in a horny heap and whimper into the floor, fingers working over her clit. Historia wondered how wet Ymir was. She could smell it, the dampness between her legs, the sweet scent of it. Her mouth absolutely watered.

What did she do first? Oral wouldn’t really work yet, not at the peak of Ymir’s heat. When it first hit, it was always the worst. Historia knew that the only thing that would satisfy Ymir for a while was her cock buried deep inside of her pussy. So she roughly pulled Ymir into a kiss and pulled at her clothes. Ymir kissed her back just as furiously, with just as much need. She didn’t let up at all, not even when they were finally naked and Historia pushed her down on the bed.

Historia forced herself away from Ymir’s addictive lips, trailed her teeth and tongue along the column of Ymir’s throat. Her teeth ached again. She wanted to bite down, to mark Ymir as _hers_ so that the entire world would know who Ymir belonged to. She rarely showed her possessive side, but it was always there. She always felt that way. Ymir shuddered at the feel of her teeth, but Historia forced herself not to bite. They would need to decide that together, when Ymir’s heat was over, when the very smell of her wasn’t driving Historia absolutely fucking wild.

Historia slid her hands downwards and between Ymir’s legs. She was absolutely soaked, hair damp and lips pink and puffy. Historia groaned deeply when she stole a peek.

“Stop teasing me,” Ymir whined, cheeks flushed. “Just fuck me already.”

Historia wanted to bristle, but Ymir said it as more of a plea than a command, and who was she not to give what her omega wanted?

 _Ymir is mine,_ Historia thought frantically, heart thundering. _Mine and only mine._

She growled and kissed Ymir again, swallowing up another moan. She grabbed her cock with one hand and guided herself to Ymir’s entrance. When she started to push in, she met slight resistance. Had Ymir done this before? She was so wet that Historia wasn’t really worried, but it took a few tries for her cockhead to finally slip inside. When it did, Ymir whined into her mouth and wrapped her long legs around Historia’s waist, pushing her down. A few inches of her cock sank in as a result and Historia nearly saw white.

This was really happening. She was really inside Ymir, feeling the silky walls of her pussy clutch and flutter around her hard, aching shaft. For years Historia had wanted Ymir, but had always been afraid that Ymir wouldn’t return her feelings because they were both alphas. She was more than simply happy to discover that she was very wrong and Ymir was _very_ good at hiding things.

“Why’d you hide this?” Historia groaned, desperate with her need to know. “Why did you never tell me?”

Ymir chuckled, melting into a long moan. She tightened her legs, making Historia sink in deeper. Historia forced herself not to move even though her muscles ached and her cock was pounding. “You never asked,” Ymir panted. “And I never went out of my way to hide it.”

“But your smell.”

“Must have been masked by the meds I took.”

Historia’s control broke and she pumped her hips forward. Ymir cried out, and then Historia’s world twisted as Ymir flipped them over. When Historia settled on her back and Ymir atop her, she sank the rest of the way down until they were skin to skin. It felt exquisite, being wrapped by Ymir the way she was, deep inside of her. They both groaned together, silent for a moment as they felt the intimacy of the moment. Then Ymir started to move, and Historia’s eyes slid shut tight.

Ymir was… definitely a top. She was the most infuriating omega Historia had ever met, even though her omega status was newly discovered. But there was a deep part of Historia that loved it. Ymir was the one using her, riding her cock hard, groaning and biting down onto her lip. Historia blinked her eyes open and watched, transfixed. Ymir was utterly beautiful like this.

Historia felt her knot form at the base of her cock, and every time Ymir descended and brushed against it, she groaned. Historia felt a deep desperation then, to knot herself inside of Ymir, come inside of her, filling her, content with knowing not a drop would go to waste.

“More,” Ymir groaned. “Please, Historia.”

 _Fuck_. She was so torn between happily laying there and letting Ymir do whatever she wanted, and taking control of the situation to fuck Ymir the way _she_ wanted. Ultimately, she decided on the latter. Sucking in a deep breath, Historia flipped them over, changing the angle and pace to her own liking. Ymir seemed to be so far gone that she didn’t seem to care.

“Do you want it inside of you?” Historia gasped at her ear. “All of me?”

Ymir groaned. “Yes, fuck. Please,” she begged. “Knot me, Historia. I’m yours.”

Historia thrust harder, faster, working her cock in until she felt ready to push. Ymir tensed against her, breaths hard, but then her body opened up and everything slid inside, and the pleasure of the moment made Historia’s entire body light on fire. She came immediately, hips jogging unevenly as she released thick jets of come deep inside of Ymir. Ymir came then too, fluttering wildly around her, milking her shaft for every bit of come until she had absolutely nothing left to give. When it was done, they both collapsed, breathing hard and hearts thundering.

Historia nuzzled against Ymir’s throat, comforted by the warm scent that she knew so well. She felt a pang of regret that she never bit her, but the satisfying burn between her legs made it bearable.

Ymir’s fingertips traced the length of her back softly, twirling in circles and shapes. Every muscle that had been tensed relaxed, and Historia absolutely melted. She could die like this, honestly. Seated deeply inside Ymir, weak from her release, warm and comforted by her feelings and by the body wrapped around her own. Ymir’s heartbeat had calmed and so had her heat, for now.

“Take your time,” Ymir whispered at her ear, fingertips still caressing.

Historia lifted her head, brow quirked. “Yeah?”

Ymir gave her a grin. There was still a glaze of lust over her eyes, a deep flush to her cheeks. “I’m not done with you yet,” Ymir told her, voice laced with desire. “Think you can keep up, my little alpha?”

Historia’s belly ignited. She gently bit down on Ymir’s shoulder, tasting the salty skin there. Ymir’s breath hitched, like she was anticipating something, and then she exhaled when Historia pressed a soft kiss against the skin. “I’ll keep up as long as you need, Ymir.”

She had a feeling that it would be a very, very long night. When Ymir flipped them over again, her mind went blank with nothing but sensation and pleasure and yeah, it was a long night indeed.

 

**Author's Note:**

> Enjoyed? Lemme know in the comments. I'm definitely going to write more omegaverse, and definitely tons of alpha!Ymir because though this was fun, alpha!Ymir is just way more my thing lmao. Thanks for reading!


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